Possible causes of left-sided chest pain when coughing include trauma, lung disease, pleural disease, or heart disease. 1. Trauma: When there is trauma to the left side of the chest, including trauma to the chest wall or trauma to the ribs, it may be accompanied by left-sided chest pain when coughing, often with a history of trauma. 2. Lung disease: there are many possible causes, such as lung inflammation, tuberculosis, lung tumor, left pneumothorax, lung abscess, etc., all of which can be accompanied by left-sided chest pain when coughing, especially when the lesion is close to the left pleura. 3. pleural disease: mainly refers to pleural inflammation, when pleural inflammation has exudation or pleural adhesion, there will be left-sided chest pain when coughing. 4. Heart disease: for example, when coronary angina attack, there will often be left anterior chest pressure-like pain, if this is accompanied by coughing, then there may be left-sided chest pain when coughing. If there is a cough when the left side of the chest pain, must go to the hospital in a timely manner, by the doctor to prescribe chest radiographs, CT and other tests, to identify the cause of treatment, so as not to delay the condition.